I've heard about these things called push pull pots that appear on Jimmy Page's Signature guitars. I know the basic stuff about them splitting the coils on the pickups but I wanna know how much it costs to install and if there are any affordable guitars that already have push pull pots.

You have to have 4-conductor pickups to do split and series/parallel operation with a push/pull.

Also, I'd like to point out that the extra switching on Page's signatures was an addition that came in the 80s and isn't going to help you sound like any of the live Zeppelin recordings. I've done the mod several times and for the most part it results in a ton of extra wires and few if any more usable tones. I'd recommend against it. If you really want something like it, I'd start with a single series/parallel switch. If you like that you can add another one for the other pickup, but I wouldn't start out by ripping out all the electronics and installing four push-pulls for the "Jimmy Page" mod.

Push pull pots are two pots in one. They are two pots deep, and may not fit in a thin solid body guitar.

Nope.

Push pull pots are pots with a switch on them.

You are thinking of dual gang pots.

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"Music snobbery is the worst kind of snobbery. 'Oh, you like those noises? Those sounds in your ear? Do you like them? They're the wrong sounds. You should like these sounds in your ear.'"
- Dara O'Briain

Yes, you get 22 sounds, but you will only use 4 of them. If you already know which 4 they are, then great, just wire for those 4 and save yourself a lot of confusion. I had to redo mine about 3 times to get it right. And it takes about an hour to undo and redo the soldering the third time, longer the first time .